SAO PAULO -- If this is to truly be Lionel Messi's World Cup, Wednesday's semifinal could prove his defining match.
Dutch manager Louis van Gaal certainly represents a decisive challenge: The arch talent meets the arch tactician, the world's greatest player meets this tournament's most influential manager. For even if Messi remains the most unpredictable player in the world, Van Gaal has come up with a series of systems that are almost impossible to second guess.
On the eve of this showdown in Sao Paulo, Argentina manager. Alejandro Sabella, even praised the Dutch coach for his ability to switch approaches midgame. That may be crucial, because Van Gaal admitted his team are going to have to adapt as the game goes on.
"I am not familiar with the line-up of Argentina," he said. "There are a number of question marks as well. They use different formations at this World Cup, so that would lead to all sorts of different reactions on our part in terms of our formation. I can't tell fortunes so will have to see with which players they will play then I will know how to proceed myself."
The problem is that they will never know how Messi is going to proceed. While even Arjen Robben's pace is predictable in some way, in that he will just run at you -- it is just exceptionally difficult to actually stop -- the Argentine no. 10 takes it to another level.
Even the languidness he showed in the group stage has evaporated. Messi is no longer just strolling near the opposition box, waiting for the opportunity to dart decisively.
That has been reflected in the manner of his contribution to Argentina's decisive moments; he is no longer just finishing moves. In the round of 16 against Switzerland, he provided the stunning run and pass for Angel Di Maria's winner. In the quarterfinal against Belgium, he started the move that led to Gonzalo Higuain's goal and might well have offered the assist of the World Cup had Di Maria been capable of maximising a divine through ball.
It was also in that quarterfinal that was best displayed the eternal dilemma that Messi poses for opposing managers.
To properly stop him, a manager basically has to detail at least three players to shuttle and shuffle him out of the game. Merely trying to challenge him with one defensive midfielder is never enough: it usually means leaving him far too much space, and thereby far too much scope to punish you.
The added problem there, however, is that committing such resources means removing so much of the conviction for your attack. If Van Gaal does decide to use more players to stop the game's single unique talent, the Netherlands simply won't have the midfield fluency to so readily release Robben.
That is the thing with Messi. He disrupts you in deeper ways than just devastating defenders.
"At the most important stage, he can always pull it off," Van Gaal enthused. "In principle, he has found it difficult to show that at a national level. He wants to change that at this tournament and we want to stop him from doing that. That will be quite a challenge."
Showdown in Sao Paulo
- Marcotti: The final push
- McIntyre: Argentina's defense rising to occasion
- Delaney: Old foes reunite in Argentina vs. Netherlands
- McIntyre: Superstars collide in Messi vs. Robben
- FC TV: What tactics will Van Gaal employ?
- Marcotti: Previewing the World Cup semifinals
- FC TV: Van Persie's fitness in questions
- Ames: Gamesmanship alive and well
Regarding how Van Gaal does that, well, it is why he has become one of the most admired coaches at this tournament. It is why he has completely banished any concerns that he is no longer modern enough to manage a club like Manchester United. The 64-year-old has been at the forefront of every tactical development in this World Cup, having set a real tone and pace with his use of 5-3-2 in the Netherlands' opening 5-1 win over Spain.
Here, Van Gaal is going to have to come with some radical, something that sets a trap. Messi is going to have be minimised while the Dutch still maximise their exceptional pace on the break. The use of Wesley Sneijder could be key and we may see something similar to the role in which he was deployed for Internazionale against Barcelona throughout the 2010 Champions League semifinal.
There was also a hint of what Van Gaal may do from a recent Dutch training session. The coach elaborated that he played 11 against nine, but only because Robin van Persie and Daryl Janmaat were out with stomach problems.
One obvious question is why the teams were arranged in that way, especially if there is a threat both may miss the game.
Van Gaal was obviously never going to offer an answer, but it may form part of his solution to this great puzzle.
Miguel Delaney is a London-based correspondent for ESPN FC and also writes for the Irish Examiner and others. Follow him on Twitter @MiguelDelaney.